


Under_Instinct

by iraewolph



Category: Undertale (Video Game)
Genre: F/M, Fantasy, Literature, Multi, Papyrus x Reader - Freeform, Rape, au sans - Freeform, fan fiction, kidnap, monster x human, monster x monster, sans x reader, undertale - Freeform
Language: English
Status: In-Progress
Published: 2016-09-05
Updated: 2016-09-05
Packaged: 2018-08-13 04:53:31
Rating: Mature
Warnings: No Archive Warnings Apply, Rape/Non-Con
Chapters: 2
Words: 5,228
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/7963189
Author URL: https://archiveofourown.org/users/iraewolph/pseuds/iraewolph
Summary: <blockquote class="userstuff">
              <p>A series of many different Undertale Characters and AU. Request will be granted if description is within boundaries.</p>
            </blockquote>





	1. Mafia Sans- Not Like the Others.

**Author's Note:**

> You know what you're getting yourself into, whether be good or bad.  
> Lemon. Sex. 18+

Mafia Sans - Not like the Others.

Sans sat at the end of his side of the bed he shared with his human partner, normally Sans wouldn't be caught dead with the fleshy being but he made an exception for her when she selflessly saved his brother from being ambushed one night, at the cost of her own safety, at first Sans assumed it was staged because out of everyone, how did this one female stop a gang with  
her Kung Fu training. Sure enough, Sans actually witness her standing up for a young monster child that was being harassed by adults, he saw her gently talk to the kid before leading him away from harm and walking him home. Exhaling the intoxicating smoke from his gap teeth, Sans figured he should show his thank you by taking her out to dinner at one of his favorite restaurants, Grillby's. If she refused, at least he could say he tried. But she didn't, she gladly accepted his invitation and it was smooth sailing from their, Sans found her humor pleasing,  
her appearance not as disgusting compared to certain others. 

Never before had the skeleton thought of taking her out again but he did, just because he had nothing better to do. But he asked her again and again... and like the first time, she said yes. One could say they were dating but Sans wouldn't, he was just having dinner with the same female for the past month. So what if he enjoyed her company, she deserved to have a good meal here and there, specially saving his little brother from potential harm. 

Then time past and before Sans knew it, it was a year and he continues to take her out but not just for dinner, he took her to the movie theater, a carnival and even his home, his hideout, his sanctuary, having a movie night with a glass of wine. Then things started to heat up when the temperature went down and avoid sounding like a complaining child, the female cuddled up closer to his boney structure. Then she got touchy, first it was just caressing his ribs through his button up shirt then his jaw line, her finger tips leaving a strange feeling in their wake, it was becoming too much, Sans couldn't seem to focus on the movie in front of him anymore. He grabbed her hand, the first hand to hand contact the two ever had . She looked up at him, believing she made him uncomfortable and she thought she was right when his left eye that always glowed blue and yellow turned hollow like his right socket. Both sockets void of light and that wide grin caused a sudden shiver to crawl on her back but she never tried to get away from him, she just stared, hypnotized. 

"Are you scared?" He asked, his usual serious tone filled the room, The human didn't realized he had turned the TV off moments ago before he stopped her actions. 

"No." She answered without hesitation.

"You should be." And just like that, his eye socket lit up with a bright blue, the dark room shifted, she found herself in a new area of his home, the two never seemed to move from their positions as they rest on top of a bed now instead of the couch that was settled in the living room down stairs. The teleportation clouded her mind, he saw it as she started to sway side to side, he smiled at her vulnerable state, humans were so weak when they wanted to be. Just as the thought was finished she touched his cheek bone and placed her plump lips to his teeth, a gesture of a kiss, no doubt. Sans stared down at her, the scent of alcohol filled the air, he chuckled to himself, she was drunk. 

He pulled her away. "Doll face, you don't know what you're getting yourself into."

"I do and I want it. Don't push me away, Sans.." She got on her knees to tower over him and wrapped her self around his neck, putting her weight on him, he allowed himself to be pushed down, the drunken woman positioned on top of him with her legs on either side of his pelvis . She kissed his teeth in gentle pecks where ever she could reach and eventually went lower to his collar bone, her lipstick smearing everywhere on his face, Sans couldn't lie, he enjoyed this kind of attention, it was when it stopped did he get confused, resting on his ribcage was the passed out woman, curled up like a small kitten. He chuckled again. Using his levitation he picked her up to get her under his covers.

"Maybe another night, Doll." He pushed her loose locks of hair back to get a good look at her face. She was so peaceful. 

 

That night was still fresh in his mind, Sans chuckles to himself at the moment, turning his head to the closed door on the opposite side of the room-light shined through the crack and a shadow could be seen moving, she was still in the bathroom,  he raised a brow bone. 

"Doll? You alright in there?" Sans called, putting the bud of his cigar in the ash tray on the nightstand. The bathroom door opened, covering parts of the dark room with it's bright light. Sans stole a glance at her, instead of her usual pajamas that consisted of one of his shirts and shorts, she was in blue lingerie, the material covering the important parts of her figure. Sans felt his grin growing. "Hm? What's the occasion" She seemed to be stuck at the door way, she couldn't even make a sound. Sans levitated her, her gown flowing in the air, giving the skeleton a free show, his magic allowed her to fall perfectly on his lap as he wrapped his arms around her waist, she was a mess, her cheeks were  bright red from the constant blush she couldn't seem to get rid of. His fingers wandered under the thin silk material that was her clothing to rub circles on her lower back and spine. She arched her back at the gentle touch. 

"It's ...my birthday." 

She answered

Sans's sockets seemed to widen, that was today, why has she not said anything, reminded him, she knew he was busy and couldn't even remember to eat most days. 

"Oh... Happy Birthday (Name)" Sans could only bring himself to say those words. 

"Thank you." She smiled. 

"So whatcha want me to give you, I'll be sure it'll arrive first thing tomorrow." Sans said, he grabbed her hands and placed her knuckles to his teeth. 

"No material things. I -I do want you though. if that's ok.."

"Ah, so you want me as your present."

"If you aren't com-"

She found herself under him, his sockets hollow as he stared down at her vulnerable state. 

"It'll be my pleasure." 

Sans's jaw unhinged, opening his mouth for the first time in ages to reveal a glowing blue tongue, the same color as his left eye. "I must warn you. I can be  a bit rough. Let me know if I'm hurting you." The skeleton monster separated her legs and made room for himself to fill in. The skeleton held a thigh in his grasp as he leaned over her to leave bite marks on her neck. Her arms wrapped around his skull and held him close to her. His hand continued to caress her thigh and detoured to her bare ass, he gave a strong squeeze before manuvering his hand to her stomach and downward towards her clitoris. 

He found it funny that his little actions got her so wet. The room became filled with her soft moans and got louder when Sans slipped a finger inside her, she was wrapped tightly around his finger. He couldn't deny that he liked it like that, how tight she was on just one phalanges, he chuckled as he added another and moving them all around inside her, stretching her walls just enough to get the party started.

By this time she had her back arched, moving her hips to get more friction going. 

'If she feels this good by just my fingers. I wonder how she's gonna handle my dick.' 

Sans continued to finger her until she was at the edge of coming but pulled out, she was panting now, a bead of sweat forming on her temple . 

"You alright Doll face?"

She squirmed at his voice, rubbing her thighs to get that same high feeling back. "Why'd you stop?"

"You don't just want my fingers do you. Just trust me. I'll take real good care of you." With that Sans got on his knees, placing her legs on his shoulders and pulling her closer to the edge of the bed. His face just inches away from her dripping wet pussy, 'his' pussy. The lack of nose didn't stop him from smelling her sweet scent, he wondered if it tasted just as good.  Wasting no time, he licked her lower lips, making sure every piece of her wasn't left untouched, her legs jerked from a jolt of pleasure and he had to grip her firmly to keep her still. Her moans and groans getting louder. 

 

"Sssssansss" 

His blue tongue entered her core and licked at her juices, his tongue was literally magic, never before has she been giving this much pleasure.

Then the taste hit him, she came within minutes, he pulled back and risen to his feet. A blue glow forming in his pants, he was finally ready. Undoing his button and zipper, Sans revealed his monster, hard and thick and ready to fuck. He positioned himself at her entrance, his arms supporting his body from crushing her. They made eye contact, admiring each other, though Sans reason was something different. From her wetnes, stretching her out, it would easy to thrust inside her, her expression, will be that of someone about to have a wonderful time. His dick head rubbed against her pussy,collecting lubricant, she stared up at him in a daze and a sweet smile, that expression wasn't it. Sans jerked forward and with great aim was inside her. She gripped his shoulders and cried out in a silence scream- there it was. Sans stilled himself, taking in her reaction. Her head leaned far back, tears freely falling as she relaxed best she could, he waited but his patience was running thin. Maybe she would tell him to stop and she'll never try this again. Sans didn't know what he wanted at this moment, he was still a bit weary of humans, they just don't trust monsters. "Leave Doll. If you want me out, just say." She shook her head and rubbed his skull in a loving manner. "Move." She did it- She took all of him, accepted him. Sans's socket shined bright as he pulled out and thrust back in at the same harsh strength, his pace slowly increasing. He couldn't seem to stop himself from groaning here and there though he tried to not enjoy as much as he was. His forehead rested on her breasts. Looking back up, panting and sweating, he saw a great deal of tears in her eyes,from pain or pleasure was hard to say but that smile was still on her sweating face. 

Could she really take him. Sans thought he should test her out. Pulling back out, he roughly flipped her around on her stomach, he reentered her again, this time quicker and rougher, she'll beg him to stop. She was pushed and pulled on his dick by her hips, she had the biggest grin on her face, tears rolling down her cheeks, she lost her voice for a second, the sound of his wet dick entering her was the only music the night was able to listen to. 

"You...are a lot.... tougher than you look, Doll face." Sans grinned, releasing her hips when she got the rhythm herself. His temperature rising to point he was sweating through his clothes, he unbutton his shirt and let it fall to the floor behind his feet. Guiding her leg he lift it to his arm and angled her sideways and continued to pump inside her, he was hitting a whole new point, the human had to plant her body where it was from moving away from his monstrous force. 

Switching positions again Sans allowed the human to be in control even if it was for a moment. Magic is such a beautiful thing, easily repositoning themself to where he was lying in bed and (Name) hovering over his dick with legs wide open, the shit eating grin on his face seemed to only grow at the sight of her, she dropped down and once again he filled her up and left her grinding against him with her tongue hanging out like a tired dog. Sans allowed himself to relax, his bones rattling as her bouncing knocked the headboard against the wall. 

The two soon paused, having to reach their end. Sans released inside of her, his cum filling in spaces he could not as she rode out her orgasm. Once she was filled with semen she moved to the side of him on the bed, panting heavily from their activity . The room smelled like sweet hot sex. Sans has never had a good night like that. He arousal soon fell, his magic faded, leaving his eyes black for a moments before two white pricks acted as eye balls due to magic drain and just being tired. He stared at her body, rising and falling chest to finally her face. 

"Was it to your liking?"

"Yes."

"Heh, you better go take a shower. No way you're sleeping in my bed like that."

"I can't move my legs." 

"I know."  Sans got off the bed, his pants already lost somewhere in his room. He went to her side and picked her up, carrying her to the bathroom. He was such a gentlemen to her. It was no surprise when he ran a shower and held her in his arms as the water fell on them, All the while, Sans French her until the water got cold and the two finally went to bed.

 

(Name) was certainly not like other humans.


	2. Masochist/Sadist Fell Sans

**Summary for the Chapter:**

> A bit of Masochist Sans and some Sadist. If you can call him that. if it sucks. Let me know and I might change it or update an entirely new one.

Sadist/Masochist Fell Sans- Choice

You know what you're getting yourself into. No warning for this guy.

You fell into the World of Monsters long ago, or maybe a week. Days were confusing down below and being locked up without a sight of light besides the candle that burned around the walls of the shed you were kept prisoner didn't help one bit. You were kidnapped as soon as you left Toriel, a crazed goat monster with a sadden heart. You started to miss her and regret leaving her ruins. At least she fed you, gave you a comfy bed and a bit of love but it was false, that much you knew, she was just using you to ignore her heartache, she must have had children and lost them and she couldn't bare it. Now, now you want nothing more than to be her detraction.

Your wrist were sore from the cold metal that was clamped around them, your legs; heavy from the lack of movement and above all, this headache that never seems to go away, being indoors, lack of fresh air, lack of meals can do that to a person. You lye motionless with your head on your shoulder, trying to sleep on your empty stomach, the pain became unbearable some time ago and the only one that knew about you had problems, the red lines under his eye sockets detect lack of sleep, his forced smile twitching every so often when he makes bad jokes and your lack of interest in him. You haven't seen him for some time and calling out to a name less monster would prove to be nothing more than getting the attention from a deaf person.

"So...hungry" You groaned after giving up on sleep.

The silence returned after you spoke those words and moments later the single door to the shed opened, the first thing to enter was the shadow of the intruder, shoes hit the wooden floorboard, creaking with every heavy step they took, finally coming into view was the kidnapper himself. The short, bulky skeleton in black, his sharp canines growing out of his mouth like a wild animal, pulled up in a Chester smile, his face sickened you and has many times caused you to puke anything that was left in your stomach.

"Hey Sweetheart. Sorry I haven't been here. I had work that couldn't wait." He spoke, his words stuttering as he spoke, in his hand was a hot dog, those strange tasting hot dogs he would choke you with since you refused to eat them willingly, by now you didn't care how they tasted, it was food and you were dying.

"I got you dinner."

He entered the cage that separated you two. He knelt down in front of you, having no strength you remained how you were, barely able to even look at end. He looked you over, the clothes you felt in hanging off your shoulders and baggy from the lack of meat on your bones. "You look different. You're losing weight." Speaking the obvious, you thought he was an idiot.

Lifting your chin up he unclenched your jaw and as gently as he could manage to the hot dog in your mouth and closed your mouth for you. Your lack of energy only had you numbing on the sausage and bun and falling out on your lap.

He looked at the piece of hotdog for a moment before speaking. "Oh you want me to baby feed you. I can do that." Going by his word, he opened his mouth wide and took a bite, he chewed and chewed and chewed until it was mushy like potatoes, a red tongue carried the goo to your mouth and without a fight you opened up. He pushed inward, the tongue going down your throat to allow the food to fall right down, He did this until the hot dog was completely gone. He chuckled and wiped the drool from his jaw with his jacket sleeve.

Your HP went up to 5/20

Why are you doing this? Why am I here?

Those questions would always enter your mind when he was here but you could never bring yourself to ask. He looked you over again, seeing your body begin to grow before it stopped just as your bones were covered by meat once again but you were still too small for your clothes.

"Are you still hungry, Sweetheart?"

"Why am I here?" You panted, speaking is a challenge in the stage your in.

"Because I like you." He chuckled and touched your waist, his boney fingers never stop touching your skin, his touch is always cold, always firm.

"This...isn't right. You don't do this to people you like. This is ...punishment." The room started to spin around you. You had to lean back on your shoulder and breathe to see straight.

 

"I'm only trying to protect you. You would have died out there.." He explained, his mouth falling to a sad smile.

"I would rather be out there and in here." Suddenly he gained an idea.

"Alright, Sweetheart. I hate this shed too. Let's take you some place else."

The chains to your cuffs hit the floor as did the one attached to your collar. He tossed you over his shoulder and left the shed. He walked past a wooden house with Christmas lights and went to the back, there was a door, opening it up with a key he stepped inside the darker room, with a switch the room was filled with bright lights. He set you to a corner and tied the chains to a pole by a desk. The room was warm, that was the only good thing about it.

Looking around, it appeared to be a small home lab. blueprints hung on walls, a cover blocking a machine no doubt on the opposite of you.

"I should have took you here along time ago. There is no way anyone would come in here."

"Why are you doing this to me? What have I done to you?"

"Nothing Sweet heart. You did nothing wrong, I really want to protect you. With your soul, we could be free but I don't want that if that means your life."

"This is crazy. Your nuts!" That was the first time in a long time you called him crazy, he seemed taken aback for a second but his smile only grew.

"Back to being feisty. Oh I missed that. Call me names again." He practically begged as he got on his knees. He was close enough to get kicked and with as much will power as you could muster, The sole of your foot connected to his face, pushing him back on his butt.

"Get away from me, freak" You hissed.

HP 7/20

The skeleton rubbed his face, groaning in pain and got back to his knees, he grabbed your foot that assaulted him and he kissed it, he kissed, licked and sucked on your toes as he never broke eye contact with you. You tried to bring your foot back but he wouldn't let you. His touch sending uncomfortable shivers running through your body. You tried jerking him and managed to hit his tooth and avoiding piercing your flesh. He came back again and this time he crawled on top of you, his face inches from you. His composer nothing more than a happy dog with his tongue out his open mouth. You cringe and pushed yourself closer to the wall to create space.

"Ohh.. I knew I picked the right girl." He cheered as he positioned himself between your open legs. his pelvis pressed against yours, you felt something that shouldn't be there but considering he has a tongue. It was a hard on. He was getting aroused from getting abused.

"Get away from me!" You screamed. "Someone help me-!" A hand covered your mouth and the force of your attacker sent your head flying back against the wall, you groaned through his fingers. "Shhh... Sweet heart. No one needs to know about this place." The skeleton looked down at you, as if in thought.

Suddenly his hands was at your hips, pulling at your pants bands, stripping you of your bottoms with ease. the only cover up being your soiled panties. You were dirty, to anyone with a nose, they could smell it, you have grown used to the smell of your own urine and fesses. "You need a bath, Sweet heart." In a flash he was gone, the room felt calmer in his absence you wanted to last for a moment, you were left looking at yourself, so distasteful. so dirty. so pathetic. Is this what your life has come down to. A mere pet to a dysfunctional skeleton. You moved around uncomfortable like, having everything dry down there coming back up to the surface. A bath did seem nice.

"Alright, Sweetheart. Lets go and try not to fight me. I would if something 'bad' happened to you."

The cuffs around your wrists were taken off and clattered on the floor at the end of you, same with the collar. The bulky skeleton picked you up by your back and knees and in an instant you were in a new location, a bathroom, hot water was running, bubbles covering the surface of the clear hot water in the tub. There were plenty of shampoo and body soap.

Having lost all energy and courage you allowed your abuser to strip you of your remainder clothing. Top, undershirt, bra and panties. He didn't seem to stare too hard because he put you in the tub once he was done. You turned your bath to him as you picked up water with your hands and jumped it on your shoulder. Deafen by bliss, you didn't hear shuffling of clothes behind you.

The water risen as new body was placed inside the tub with you, the water turned off by the new comer, the skeleton was smaller with his clothes off as you stared at him with distaste but didn't say anything. He simply picked up a bottle and leaned over you, you pulled back when your space was invaded but he only got closer until you were at a dead end. He pour the scented liquid on your head, his smile getting wider when you no longer tried to move.

"Relax, Sweet heart. I'm only washing you." You would have been lying if you said his boney fingers didn't feel good on your scalp. You turned your back towards him again and leaned down, trying to get your hair damped to activate the shampoo. The skeleton seemed to smile kindly as you finally allowed him to wash you. In no time, all the crusty unwanted 'nature' was off your skin, you seemed to smile yourself, it felt so relaxing to finally get a bath after so long. You were too weak to clean yourself now that you thought about it. You felt so tired.

The quietness becoming music to your ears as you were able to fall asleep but that song ended too soon when a loud voice rang through the walls of the house. "SANS! I'M HOME!...WHERE ARE YOU, YOU BAG OF DUST!"

You squeaked and tried to get out the tub but who you could guess to be Sans held you down to him, covering your mouth yet again and quietly he whispered. "Relax Sweetheart!"

"welcome home, b-boss. i'm in the bathroom!" Sans called back. Footsteps could be heard walked up stairs, and the voice from before yelled through the wooden door. "HURRY IT UP IN THERE. YOU DON'T PAY THE BILLS!"

"w-will do, boss." The foot steps descended from which they came. Sans lowered his hands and rest it on your shoulder before moving your hair to the other side. Your skin seemed to glow and Sans found himself hypnotized. He panted quietly, his tongue rolling out his open mouth, the desire to want to taste it easily over powering his mind and common sense. He licked you, long and slow, it took you awhile to reprocess what he was doing but when you did, you cringe and tried to move away from him.

It was a strange wrestle in the bath tub, water spilling on the floor, damping the rubs that lay out, it was another fight you lost in.

Sans unclogged the tub and wrapped you in a towel off the rack. Teleporting again, you ended up in a bed room, nice and neat with bottles of mustard sacked on a desk. You were placed on the covers of the bed and toweled dry.

"Do you feel better now, Sweet heart?" His skull was sweating. Biting the inside of your cheek you nodded your head at his question.

"Good...I'm glad... uh... stay here... I will go get you some clothes." He chuckled as he stared at you a bit longer, now that you were clean, you looked much more attractive like how you were when he took you though you still lost a lot of weight during those times. Sans, redressed in clean clothes, left the bedroom, locking it from the other side. You sighed and just collapsed on the bed and fell asleep just as your head hit the soft cotton pillow.

 

Night fell, if one could say that when you were woke up by your own moaning. Your body was being jerked up and down, and you felt pain between your legs. It took you a moment to know what was going on and when you did, you were struck paralyzed. On top of you with a satisficing grin was Sans. His eyes were closed staring up at his ceiling. He was raping you. You couldn't find yourself to move or scream, you were just lying there as he thrust inside of you but how, he's a skeleton, there should be nothing there but your womanhood begged to differ. He filled you up better than any guy you went out with on the surface by far but it was still wrong. How long was he at this? Why can't you move? These questions shouted at you as if you knew the answers.

Then he hit it, that sweet spot that caused a louder sound to escape your lips. Sans paused hearing your voice say his name for the first time and he looked down at you, his left eye socket glowing crimson red much like his tongue. "H-hey...Sweet heart. Sleep well." He stopped his movements and panted, his forehead resting between your breasts as he held you close. You felt hot all of a sudden, you felt needy. Sans never moved from out of you so when you finally were able to move your body you felt his hardness hit your walls, you moaned again and kept that up, trying not to get him to noticed too soon but he figured it out, he pulled nearly all the way out before coming back in. "Does it feel good, Sweetheart? Does it?" Sans asked, as if your opinion really mattered to him. 

"Keep going." Practically begging him to fuck you again.

The mattress moved with his hard quick movements, you eventually had to cover your mouth to keep that other one from knowing. Sans's solution.

Flipping you on your stomach and having you bite the pillow as he penetrated you repeatedly. He doesn't seem to run out of energy, unlike you that was getting tired and dizzy from it all or was that the many orgasms he kept giving you.

Sans moved your body to his will, having you on your side with a leg over his shoulder, he tightened you around his dick again, having a much difficult time going in and out but loving the challenge nonetheless. Your face flushed red, throat dry from the covered screams. You felt your life points draining from your very existence until you felt like nothing more but his sex toy. His sweet candy.

The bulky skeleton's red tongue licked around your mounds ending at the bud and giving it a suckle. Sans's finally pulled out and drowned you in his hot white semen that exploded out of him. He bit your shoulder as he was coming off his high, his fangs going in deep, blood oozed out of the holes in your flesh. Your blood giving his taste buds a fill of bliss as he lapped it up as he felt you tighter.

You have never felt more sore before than you are in right now. Your vagina pulsed repeatedly as if it was having asthma , your heart beating against your rib cage with each deep breath you took. Sans was chuckling like a school girl when he finally fell to his side and stared at you. "Oh Sweet heart. I'm definably keeping you as my pet."

Not like you had a choice.


End file.
